Trial Harbour substation electrical clearance checks

Client: TasNetworks
Location: Tasmania, Australia
Date: April - May 2022 

Using modelling software to confirm electrical clearances for safe operation of a 44/22 kV substation


TasNetworks owns and operates a 44/22 kV substation at Trial Harbour on Tasmania’s West Coast. This zone substation supplies power to Tasmania’s West Coast community in Trial Harbour and surrounding areas.

The substation was designed and constructed in 2007 to 66 kV, but was operating at 44 kV. It is set to commence operation at 66 kV after an upgrade of the connecting infrastructure.

TasNetworks engaged Entura to perform electrical clearance checks of the substation, to identify any substandard electrical clearances to live equipment and to optimise access to the 44 kV circuit breaker control box.


Entura attended the site and performed a point cloud scan of equipment within the substation boundary, including all air-insulated primary plant and pole-top station services transformers. We also scanned underneath and inside the 22 kV switchgear and control building to provide TasNetworks with a complete scan of the site for future reference.

The scans were processed into an Autodesk Recap 3D model format, which enabled electrical clearance checks to be performed to Australian Standard AS2067. Site clearances were checked for both 44 kV and 66 kV. Because the 44 kV voltage is uncommon in modern Australia and doesn’t exist within the AS2067 standard, Entura performed the checks using internally developed electrical clearances extrapolated from the AS2067 clearance values. We also checked the 22 kV station services transformer conductor connections phase-to-phase and phase-to-earth clearances.

The clearance check included all air-insulated assets within the substation from the point of the transmission line connection, including horizontal work clearances, section safety clearance, vertical work clearance, station services transformers and boundary clearances, such as from the boundary fence to live parts within the substation.

We also performed specific clearance checks and provided guidance on the modifications and measures required in order for TasNetworks to install steps or a platform to grant better and safer access for operating staff to the 44 kV circuit breaker control box.

Services provided

  • Site point cloud scan
  • Autodesk Recap 3D modelling
  • Electrical clearance checks
  • Primary electrical design
  • Construction supervision


By using a point cloud scan and 3D modelling – which is a more accurate representation of a site compared to conventional 2D drawings, which can often be inaccurate or out of date – we were able to quickly and accurately check the electrical clearances and summarise findings for TasNetworks so that our client could ensure that all clearances are appropriate and that the substation can be operated and maintained safely.